1Vertical structures Prof Schierle 1V e r t i c a l S t r u c t u r e sHeight motivations: express power religion symbol visibility wind powerVertical structures Prof Schierle 2Cheops Canary Empire Petronas Sears Taipei Burj Burj Pyramid Warf State Towers Tower 101 Dubai DubaiGiza London New York Kuala Lumpur Chicago Taipei Dubai DubaiVertical structures Prof Schierle 31776 US Declaration of Independence2Vertical structures Prof Schierle 4Vertical structure linksCTBUH: Council of Tall Buildings and Urban Habitathttp://www.ctbuh.org/http://www.archdaily.com/tag/ctbuh/CTBUH awardshttp://en.wikipedia.org/wiki/CTBUH_Skyscraper_AwardCTBUH conferenceshttp://www.ctbuh2012.com/http://www.ctbuh.org/Events/Conferences/tabid/74/language/en-GB/Default.aspxMost Skyscrapershttp://www.emporis.com/statistics/most-skyscrapershttp://twistedsifter.com/2011/11/top-25-cities-with-most-high-rise-buildings/http://en.wikipedia.org/wiki/List_of_cities_with_the_most_high-rise_buildingshttp://www.terragalleria.com/pictures-subjects/high-rise-buildings/High-rise fire:http://911research.wtc7.net/wtc/analysis/compare/fires.htmlJapan quake 2011:http://www.youtube.com/watch?v=1JQBGOliAcQWind Engineering:http://en.wikipedia.org/wiki/Wind_engineeringhttp://ascelibrary.org/doi/abs/10.1061/41016(314)285Risk Assessment:http://www.academia.edu/1391325/Performance-Based_Aeolian_Risk_assessment_and_reduction_for_tall_buildingsHigh-rise publications:http://www.amazon.com/s/?ie=UTF8&keywords=highrise+architecture&tag=googhydr-20&index=stripbooks&hvadid=18556336517&hvpos=2t4&hvexid=&hvnetw=s&hvrand=820989502673924540&hvpone=&hvptwo=&hvqmt=b&ref=pd_sl_68lit4kpn1_bVertical structures Prof Schierle 5reading room = 60 psfstack room = 150 psfLibrarylight = 125 psf heavy = 250 psf Manufacturingfixed seating = 60 psf movable seating = 100 psf Assembly50 psfOffice40 psf Residential and schoolsASCE 7 Table 4.1 excerpts of common live loadsASCE 7, page 10Live load reduction Since large members are unlikely fully loaded, ASCE 7 allows live load reductions (except for public spaces and LL ≥ 100 psf):For members supporting ≥ 600 sq. ft.Reduction shall not exceed 50% for members supporting 1 floor, 60 % for members supporting 2 or more floorsVertical structures Prof Schierle 6Alternate 1:Standard framingBraced frame optimization3Vertical structures Prof Schierle 7Alternate 1:Standard framingAlternate 2:Tapered steel beams $12,000 moreRectangular ducts $3,000 moreReduced curtain wall $120,000 lessSavings: S105,000Moment frame optimizationVertical structures Prof Schierle 8Structure systems vs. building height, by Faslur KahnVertical structures Prof Schierle 9Structure weight (steel structures)Structure weight per floor area defines efficiency. Structure weight for gravity load increases only slightly with height. Structure weight for lateral load, however, increases substantially.1 Structure weight vs. building height by Fazlur Kahn2 Structure weight per floor area of actual buildingsA Number of storiesB Structure weight in psf C Structure weight in N/m2D Structure weight for floor framing onlyE Structure weight for gravity load onlyF Structure weight for gravity and lateral optimizedG Structure weight for gravity and lateral not optimizedStructure weight for various buildingsH Empire State building New YorkI Chrysler building New YorkJ World Trade center New YorkK Sears tower ChicagoL Pan Am building New YorkM United Nations building New YorkN US Steel building PittsburghO John Hancock tower ChicagoP First Interstate building Los AngelesQ Seagram building New YorkR Alcoa building PittsburghS Alcoa building San FranciscoT Bechtel building San FranciscoU Burlington House New YorkV IDS Center MinneapolisW Koenig residence Los Angeles4Vertical structures Prof Schierle 10Vertical / lateral systems1 Shear walls are least flexible but good for apartments and hotels with party walls2 Cantilevers provide the least intrusion at ground floor3 Moment frames are most flexible, good for office buildingsA Concrete moment resistant joint:rebars extend through beam and columnB Steel moment resistant joint: beam flanges welded to column flanges; stiffener plates between column flanges resist bending stress of beam flanges4 Braced frames are more flexible than walls but less flexible than moment frames bracing is usual around central coresBBBBBBBVertical structures Prof Schierle 111 X-direction concentric, Y-direction eccentric2 X-direction eccentric, Y-direction eccentric3 X-direction concentric, Y-direction concentric4 X-direction concentric, Y-direction concentric5 X-direction concentric, Y-direction concentric6 X-direction concentric, Y-direction concentricConcentric & eccentric shear wallsNote: eccentric shear walls cause torsion and should be avoidedShear wallsNote: shear walls resist lateral load only parallel to wall1 Shear walls resist only lateral load parallel to wall2 One-way shear walls collapse @ perpendicular load3 Eccentric shear walls cause torsion4 Concentric shear walls resist torsionNote: Walls in 4 are offset but provide concentric support Vertical structures Prof Schierle 12 Platform framingPlatform framing is used for low-rise residentialstructures, due to economy & flexibility. 2x4 studs@ 16” reach from platform to platform. Doubletop plates overlap at corners and splices. Plywoodsheathing, nailed to studs, resists lateral wind andseismic loads. Joists, usually 2x12 @ 16” supportplywood floor and roof (platforms). Blockingresists joist buckling and supports plywood paneledges to transfer shear. Standard plywood andgypsum board panels 48” (4’)widematch2,3,or4joist/stud spaces of 24”, 16” or 12”, respectively.A Joists, 2x12 or 2x10 @ 16", 24“, or 12” o.c..B